Idiomarina gen. nov., comprising novel indigenous deep-sea bacteria from the Pacific Ocean, including descriptions of two species, Idiomarina abyssalis sp nov and Idiomarina zobellii sp nov.

Two bacterial strains, KMM 227(T) and 231(T), were isolated from seawater s amples collected from the north-western Pacific Ocean at a depth of 4000-50 00 m and were characterized using polyphasic taxonomy, Both were Gram-negat ive, psychrotolerant, heterotrophic, aerobic and required NaCl for growth ( 0.6-15.0%). The temperature for growth was 4-30 degrees C. Both strains wer e rod-shaped, with a single flagellum, However, strain KMM 231(T) revealed a single long fimbrium, Cellular fatty acids detected in the isolates were predominantly odd-numbered and iso-branched, with 15 and 17 carbons (ca. 70 %), Also present were saturated and monounsaturated straight-chain fatty ac ids. Results of phylogenetic analyses, employing three tree-making methods, strongly indicated that the two strains formed a distinct lineage within a clade containing the genera Alteromonas, Colwellia and Pseudoalteromonas. in the gamma-Proteobacteria, The two strains shared 16S rDNA sequence simil arity of 96.9% and genomic DNA relatedness of 27%; the latter was determine d by dot-blot hybridization, The strains were differentiated by the presenc e of fimbria, production of chitinase, ability to grow on 15% NaCl and BIOL OG profiles. Given the polyphasic evidence accumulated in this study, it is proposed that the two deep-sea isolates be classified in the genus Idiomar ina gen, nov., as Idiomarina abyssalis sp, nov. (type strain is KMM 227(T)) and Idiomarina zobellii sp, nov. (type strain is KMM 231(T)).